1. Field of the Invention
This invention relates to the manufacture of devices and, in particular, the manufacture with gases of electronic devices.
2. Art Background
The manufacture of many electronic and optical devices involves the formation of materials from gas phase precursors. For example, integrated circuits based on GaAs have just become commercially viable for specialty applications and rely on precursors such as arsine. Additionally, compound semiconductor materials, e.g. III-V materials such as gallium arsenide phosphide, indium gallium arsenide phosphide, indium gallium arsenide, indium arsenide, indium aluminum arsenide phosphide, gallium aluminum arsenide, and gallium arsenide antimonide, formed from precursors such as arsine, phosphine and stibine, are widely used in the fabrication of solid state lasers, light emitting diodes, field effect transistors, and photodetectors.
A variety of gas phase fabrication procedures such as metal organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (VPE), molecular beam epitaxy (MBE), and gas source MBE are available. In these procedures, precursor gases are utilized that interact with other precursor gases and/or with an energy source, i.e. heat, to yield formation of the desired material. Many common precursor gases such as arsine are quite toxic or present other handling considerations. (See The BOCA.RTM. National Fire Prevention Code/1987 Building Officials and Code Administrations, Int. Inc. 7th Ed. Country Club Hills, Ill. 60477, for a review of a variety of procedures utilizing precursors such as arsine in the fabrication of devices.) Although perfectly adequate devices have been made, the precursor is typically supplied from a compressed gas cylinder. For gases having properties such as high toxicity, the catastrophic failure of a compressed gas cylinder or lines leading directly from such cylinder is undesirable.
Few approaches to reduce possible problems associated with storage of large quantities of gases in device fabrication are available. In one approach, arsine is generated through the catalytic interaction of copper arsenide and phosphoric acid. The reactants are controlled so that the arsine generated is limited to the quantity necessary for immediate use in device fabrication. These processes produce arsine at a relatively low rate. Typically, arsine pressures less than 150 Torr are generated. Additionally, the subsequent disposal of the catalytic material and byproducts poses a significant problem. Thus, totally acceptable approaches for device fabrication utilizing a source of gas, other than a compressed gas source, are not presently available.